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(No Model.) 3 SheetsSheet l. J. P. FREEMAN.

TELEPHONE TRANSMITTER.

No. 318,423. Patented May 19, 1885.

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TELEPHONE TRANSMITTER. v No. 318,423. Patented May 19, 1885.

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IlNiTEE STATES- PATENT Erica,

JAMES P. FREEMAN, OF CHICAGO, ILLINOIS, ASSIGNOR OF NINE TIVEX- TIETHS TO E. M. MARBLE, OF \VASI-IINGTON, DISTRICT OF COLUMBIA.

TELEPHONE-TRANSMITTER.

To (ZZZ whom it may concern.-

Be it known that 1, JAMES I. FREEMAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in TelephoneTransmitters, of which the following is a specification, refer ence being had to the accompanying drawings.

My invention relates to telephonic transmitters of the class known as battery-transmitters, and its object is to utilize for telephonic transmission an intermittent electrical current instead of the so-called continuous undulatory current employed in variable-contact closed circuit transmitting-instruments as heretofore constructed.

My invention in part consists in breaking and closing the primary circuits of an inductioircoii rapidly in response to the vibrations of a diaphragm actuated by sound-vibrations of the air, and thereby causing said circuits to be traversed intermittingly by strong electric impulses, which have the effect to induce in the secondary circuit and the line-wire connected thereto impulses of alternating direc tion, having quantity and tension so great that they will travel over very long stretches ofline-wire,an d actuate receivirig-instruments connected therein with greater force than has heretofore been known in the art of telephony, reproducing articulate speech clearly, loudly, and distinctly; and in part in a novel combination, in a transmitting-instrument,0f circuit closing and breaking devices with a dia phragm, battery-circuits, and an inductioncoil having two primaries and one secondary coil, which will be hereinafter more fully described, and pointed out in the claims.

In the accompanying drawings, forming a part of this specification, and in which similar letters refer to like parts, Figure l is a perspectivc view of the door of a transmitter box or casing having mounted thereon the diaphragm and circuit closing and breaking devices. Fig. 2 is a view in elevation of the transmittenbox with its door open to show the interior parts. Fig. 3 is a section of the door and diaphragm in the plane of the vertical diameter of the latter, the. circuit closing and breaking de vices and induction-coil being shown in full *PECIFICA'IION forming part of Letters Patent No. 318,423, dated May 19 1885.

Application filed January 14, 1885.

(X0 model.)

lines. Fig. I is a detached end elevation of the working-lever and electrodes. Fig. 5 is a section of the door and diaphragm and view in elevation of an induction'coil and circuit closing and breaking devices of modified construction. Fig. 6 is a diagram illustrating another modification of the circuit closing and breaking devices in connection with an induction-coil. Fig. '7 is a longitudinal diainetric section of a preferred form of induction-coil.

Referring to Figs. 1, 2, 3, and 4, the letter A indicates the box or casing of the apparatus, and A is its door, having the diaphragm I) mounted behind an orifice, a, therein in the usual manner. From the center of the rear surface of the diaphragm projects a pin, 0, and behind this pin is an approximately-equal-armed rocking lever, F, pivoted to an arm, f, which stands behind the diaphragm and is supported by a post, f, projecting rearwardly from the door A. This rocking lever F has inserted through openings in its ends insulating Ol'1lOl1-COll(IllCting plugs g g, and through these plugs are secured metallic pins h h, the forward ends of which are arranged to make contact with the tips of metallic spring-fingers I I, which pro jcct from the door A and stand at a little distance from the rear face of the diaphragm.

Ihe rear'ends of the pins h 71/ are arranged to make contact with the respective carbon electrodes K K, carried by metallic strip-springs 7t 7t, projecting from metallic spring-arms Z I, which project rearwardly from the door A. Each of these spring-arms has behind it a post, Z, through which passes an adjustingscrew, Z, the tip of which bears against said arm. By means of these screws the arms may be adjusted to cause the springs to hold the carbon electrodes in proper relation to the contact-pins. These spring-fingers, springarms, electrodes, rocking lever, and contact pins constitute, in connection with the diaphragm, the circuit closing and breaking de vices, and with them I use an inductioircoil of peculiar construetion,in that it has two primary coils, one of which is preferably ar ranged within the secondary coil in the usual manner, while the other is wound outside of the secondary coil. I have illustrated such an induction-coil in Fig. 7, though I wish it to be understood that I do not confine myself to this form, the essential requirement being only that there shall be two primary coils which act alternately for inducing currents in the secondary. ondary coil, m the inner primary, and m the outer primary, coil. Now, in connecting this coil for use I connect the outer terminal of the outer primary coil with the spriugarm Z, and the inner terminal with one pole of a battery, X, which has its other pole connected with the spring-finger I. The outer terminal of the inner primary coil is connected with the springarm Z, and the inner terminal of this inner primary coil is connected with one pole of a battery, X, the other pole of which is con nected with the spring-finger I. It will now be seen that if the spring-finger I is in con tact with the forward end of contact-pin 71.,and the rear end of said pin is in contact with the carbon electrode K, the circuit of battery X will be closed through the spring-finger I, contact-pin h, carbon electrode K, strip spring 7r, arm Z, and the conductors, including the outer primary circuit, which connect said arm and spring-finger I with the opposite poles of the battery. tact with its adjacent spring-finger and carbon electrode, the pin it should be in contact with the spring-finger I and carbon electrode K, then the circuit of battery X would be closed through the inner primary circuit, as will be readily understood.

The actual mechanical arrangement of the conductors and other parts is illustrated in Fig. 2, in which the induction-coil is indicated by M, and w w are the terminals of its secondary coil leading to binding-posts 3 y. The outer terminal of the outer primary is connected by a wire, 10, with one side of the lower door'hinge, j, from the other side of which a wire,w*,leads to an arm ,1. The inner terminal of the outer primary is connected by a wire, 10", with binding-post a, which is to be connected with one pole of the battery X, the other pole of which is to be connected with binding-post .6, which is connected by a wire, 20, with one side of hingej, the other side of which is connected by a wire, wflwith spring iinger I. The outer terminal of the inner p imary is connected by a wire, to, with one side of hingefithe other side of which is connected by wire 10 with arm Z, while the inner terminal of this inner primary is connected by a wire, 10*, to binding-post z. This post is to be connected with one pole of battery X, the other pole of which is to be connected to bind ing-post 2' which is connected with one side of hinge j, the other side of which is connected by a wire, to", wit-h spring-finger I.

The pin a, at the center of the diaphragm, touches the inner side of the rocking lever F at one side of its pivot and at a point nearer to pin 71. than to pin 71. The carbon electrode In the figure, M is the see If, instead ofthc pin it beingin con--- K is adjusted tobear'normally but lightly on the inner end of pin h, and said pin is always in contact with the spring-finger I. The circuit of the batteryX is thus normally closed through the outer primary coil of the induction-coil. At this time pin h is in contact with spring-finger I and just out of contact with carbon electrode 1'. Now, if the diaphragm makes an inward half-vibration it moves the rocking lever F to force the pin h into contact with carbon electrode K and break the contact of pin it with carbon electrode K, thus breaking the circuit of the outer primary coil. As the spring-finger I follows pin h and never breaks contact therewith,the circuit is closed through the inner primary coil as soon as said pin touches the carbon electrode K,which is immediately after the breaking of the contact between pin it and carbon K. Both the closing of one and the breaking of the other produce inductive effect uponthc secondary,and the winding or direction of current in the two primaries is such that the breaking of one induces a current in the same direction as does the closing of the other, and their combined effect is to induce in the secondary very powerful impulses,which flow on the connected line and actuate with great forcethereceiving-instrumentsincluded therein. The outer half-vibration of the diaphragm of course restores the parts to their normal position, breaking one circuit and closing the other.

' \Vhile it is true that there is an instant of time between the breaking of one primary circuit and making of the other, and vice versa, the making and breaking of said circuits are so rapid that every word and every part of every word spoken in front of the instrument is taken up and transmitted clearly and distinctly. This result is due to the peculiar construction ofthe instruments embodying the invention in each of the forms shown.

In the modified construction of the circuit closing and breaking devices illustrated in Fig. 5 the carbon electrodes K K are supported in the same manner asshown in Fig. 1, the only difl'erence being that they project inwardly from the door on opposite sides of the diaphragm. In this modification the rocking lever F has one insulated contact-pin, h", at only one end, while at the other end a pin, h, in metallic connection with the lever, is arranged to make contact with the carbon electrode K. There is but one lower spring-finger, as at I, and it is arranged to make contact with the forward end of pin if, while the rear end of said pin makes contact with the carbon electrode K. The pin a, at the center of the diaphragm, touches the rocking lever l on one side of its pivot nearest the pin it"; The spring-finger 1* is constructed to press the pin into normal contact with the carbon electrode K, and at such time the pin h, at the other end of the lever, is just out of contact with the carbon electrode K.

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The outer terminal of the outer primary coil of the induction-coil M is connected by a wire, with one pole of the battery X the other pole of which is connected by a wire, 10, with the spring-finger I and the inner terminal of this outer primaryis connected by awire, ar with the arm Z, supporting the stripspring 7:, which carries the carbon electrode K. The outer teminal of the inner primary coil is connected by a wire, with one pole of a battery, X, which has its other pole connected by a wire, 10, with the arm f, which supports and is in electric connection with the rocking lever F, and theinner terminal of said inner primary is by a wire, a, connected with the spring-arm Z, supporting the strip-spring 7;, which carries the carbon electrode K.

The secondary circuit of the induction-coil is to be connected to line the same as in the first-described instrument.

The pin If, in the normal condition of the instrument, is always in contact with springfinger I and the carbon electrode K is alsoin light contactwith the inner end of pin h and the pin h is just out of contact with carbon electrode K. Now, when the diaphragm D moves inwardly the pin 0 forces the lever F in such direction asto put the pin h in contact with the carbon electrode K, thus closing the circuit of battery X", and at the same time the pin h is carried down out of contact with carbon electrode K, thus breaking the circuit of battery X The circuit being thus closed through one primary coil and broken through the other, the same inductive effect is prol duced upon the secondary as in the first-described form of the apparatus.

In the modified form of the apparatus illustrated in the diagram Fig. 6, an arm, C, projects inwardly from the center of the diaphragm D. An equal'armed lever, F is pivoted at one side to the inner end of this arm by means of a projection, f", and at its other side it is pivoted by a similar projection to the end of a bent arm, F, projecting from the door of the box. From the opposite ends of this equal-armed lever pins 1:" and 0" project downward, and are arranged to make contact alternately with carbon electrodes K and Ii", which are supported by springs s s. (Shownin section.) Theinner terminal ofthe I enter primary coil of the induction-coil M is connected by a wire, w", to one pole of a bat tery, X, the other pole of which is connected by a wire, 10", to pin It on arm of lever P,

which is next to the diaphragm, and the outer i terminal of said primary is connected by a wire, or, with the carbon electrode K. The

inner terminal oi the inner primary is con nected by a wire, w", with one pole of a battery, X which has its other pole connected by a wire, air, with the pin h on arm of lever F which is turned away from the diaphragm, and the outer terminal of this inner primary is connected by a wire, to, with the carbon electrode K. This apparatus will be normally constructed so that the pin at the end of lever F next to the diaphragm will be lightly in contact with carbon electrode K", and the pin at the other end will be just out of contact with carbon electrode K". Now, when the diaphragm moves inwardly the arm 0 will rock the lever F so as to raise the pin at the end next to the diaphragm out of contact with carbon electrode K, while throwing the pin at the other end in contact with electrode K. Thus the circuit will be alternately closed and broken through the respective primaries of the induction-coil with the same effect of double induction produced by the two forms of the apparatuspreviously described.

I make no claim to the mechanical construction of the instrument herein described, as that is claimed in my application filed April. 21, 1885, which is a division of this applica; tion.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The method of transmitting articulate speech telephonically which consists, first, in

.causing primary intermittent electrical im pulses in the transmittingcircuits through the agency of sound-waves due to articulate speech; secondly, causing said primary impulses to generate secondary electrical impulses of an alternating nature thirdly, cans ing said secondary electrical impulses to actuate a rcceiving-telephone at a distant station and reproduce said articulate speech accurately and clearly, substantially as described.

2. The method of transmitting articulate speech lelephonically by causing intermittent electrical impulses to traverse an electrical circuit, and thereby gene ate secondary elec trical impulses,which secondary electrical impulses in turn actuate a telephone-receiver and causeit to accuratelyreproduce the aforesaid articulate speech, sul'istantially as described.

In testimony whereof I at'lix my signature in presence of two witnesses.

JAMES fl. l HEEIL-rX.

\Vhnesses:

(initiates llrnn, Russian. ll. Room.

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